Mold box and method of manufacturing a block

ABSTRACT

The present invention relates a mold box method of manufacturing a block, and a wall block with a stepped-back strata and ledges imprinted on one or more faces of the block. A mold box is provided with a block face liner that is machine cut to create a particular strata and ledge pattern that is widest at the top of the liner and steps back over a plurality of planes to a narrower width at the bottom of the liner. Masonry material is allowed to form in the mold box around the liner to produce the strata and ledges imprint onto one or more faces of the block. The invention also relates to the mold box, multiple embodiments of the block face liner with differing strata and ledge patterns, and to blocks formed in the mold box and methods of constructing walls with the blocks.

This application claims the benefit of U.S. Provisional Application No.60/944,177, filed Jun. 15, 2007, entitled “Method of Manufacturing aBlock”, the contents of which are hereby incorporated by referenceherein.

FIELD OF THE INVENTION

This invention relates generally to a method of manufacturing a block,the block and walls constructed from such blocks. In particular, thisinvention relates to a block manufactured with a one or more faces thathave a plurality of irregularly contoured strata and ledges on aplurality of planes.

BACKGROUND OF THE INVENTION

In the manufacture of retaining wall blocks and other kinds of blocksmade from concrete, it is common to use a mold that forms a block modulewhich is then split to form two or more blocks. When a block module issplit, the split surface has an irregular appearance, which is desirableif the desired look is one of natural stone. A split block appearancehas a desirable appearance for many applications, such as retainingwalls and landscaping products.

A typical retaining wall block has substantially parallel top and bottomsurfaces and substantially parallel front and back surfaces. Sidesurfaces may have various angles or contours relative to the front andback surfaces, or could also be substantially parallel. In forming blockmodules of such blocks, it is often standard practice to split a blockmodule on a plane coincident with the front faces of two blocks, thusgiving the front faces of two opposing blocks an irregular (i.e.,roughened) appearance.

U.S. Pat. No. 5,827,015 describes the conventional dry castmanufacturing process used to manufacture concrete wall blocks. In suchprocess, a mold box is used to form a block module or slab that issubsequently split into two wall blocks. It is also known to providemold boxes which can simultaneously form multiple slabs of identicalsize and shape.

Another important feature of retaining wall blocks and blocks used infree standing walls is the appearance of the block. The look ofweathered natural stone is very appealing for walls. There are severalmethods in the art to produce concrete wall blocks having an appearancethat to varying degrees mimics the look of natural stone. One well knownmethod is to split the block during the manufacturing process so thatthe front face of the block has a fractured concrete surface that lookslike a natural split rock. This is done by forming a slab in a mold andproviding one or more grooves in the slab to function as one or moresplitting planes. The slab is then split apart to form two or moreblocks. Another method is wherein blocks are individually formed in amold and the surfaces are textured by removal of the mold. Additionalmachine texturing processes can then be applied. Many manufacturers alsovary the color and the texture or pattern on the front face of theblock. It might be desirable for the face of the block to be smooth,serrated, or grooved or to have an aggregate appearance.

Another method to create a weathered stone appearance is to tumble theblocks together with other blocks in a large rotating canister. Thecollisions of the blocks in the tumbler chips off random pieces of theblocks, rounding the edges and creating a look that can be quite closeto the appearance of a natural stone. This is a labor intensiveundertaking that also can result in undesirable damage to the blocks andhigh overall costs of production.

Another known method of creating a block having an irregular or texturedsurface is to form the block in a mold box that has been provided with asidewall liner shaped to impart the irregular or textured surface on theblock during the block molding process. The block is formed in a cavitybounded by a pallet upon which the mold box rests and the sidewalls ofthe mold box. After the material which forms the block has set enough toretain its shape a compression head having a stripper shoe positionedabove the top of the mold box is used to compress the material and urgeit out through the bottom of the mold box. The block remains on thepallet and is moved to a curing station. Since the block material isremoved out the bottom of the mold box the side walls of the mold boxare typically angled outwardly towards the bottom of the mold box at aslight angle which may be between about 1 to 5 degrees. This reduces thepossibility that the material will hang up in the mold box duringremoval due to either vacuum or suctional forces caused by remainingliquid in the material or undercut areas in the side wall.

Creating a random, or ashlar, pattern in the face of a wall is highlydesirable. This gives the appearance of a mortared or dry-stackednatural stone wall, which is a traditional and well accepted look. Somecurrent wall blocks are intended to create an ashlar pattern. However,the creation of a truly random appearance requires the production ofmultiple block shapes for use in a single retaining wall. This isinefficient from a production standpoint because this requires multiplemolds and more kinds of blocks to inventory. If only one face of theblock is intended to be the front face, then the block system willsuffer a trade-off between having enough face sizes to create a random,natural appearance and the cost and inefficiency of using multiple moldsand creating multiple inventory items.

It would be desirable to have a method of manufacturing blocks for awall that provides for an attractive appearance of a natural ledge orashlar stone wall with a cost-effective and easy to installconstruction.

It would be further desirable to provide the face of the block withirregular contours of multiple strata and ledges on a plurality ofdifferent planes to enhance the dimension and depth of the block faceand thus the wall constructed with such blocks.

It would be further desirable to create such blocks from a single moldwith multiple different strata and ledges patterns to increase thevariability and randomness of the block wall.

SUMMARY OF THE INVENTION

The present invention relates a method of manufacturing a block that hasa stepped-back strata and ledges imprinted on one or more faces of theblock. A mold box is provided with a block face liner that is machinecut to create a particular strata and ledge pattern that is widest atthe top of the liner and steps back over a plurality of planes to anarrower width at the bottom of the liner. Masonry material is allowedto form in the mold box around the liner to produce the strata andledges imprint onto one or more faces of the block. The invention alsorelates to the mold box and to blocks formed in the mold box and methodsof constructing walls with the blocks. Multiple embodiments of the blockface liner for the mold box are disclosed for enabling blocks withdiffering strata and ledges formed on the faces of the blocks to beformed in a single mold box by changing the liner.

In one aspect the present invention is a wall block mold including firstand second opposing side forming surfaces and first and second opposingface forming surfaces, the first and second side forming surfaces andfirst and second face forming surfaces being positioned to form aperimeter of a mold cavity in the shape of a wall block. The wall blockmold also includes at least one of the face forming surfaces having astepped surface contour which steps outwardly from a top of the moldcavity to a bottom of the mold cavity, the stepped surface contourdefining a plurality of planar surfaces, each planar surface having anon-linear edge, each non-linear edge of a planar surface being joinedto a non-linear edge of an adjacent planar surface by a ledge, eachplanar surface being angled outwardly from vertical in the direction ofthe bottom of the mold cavity by an angle α which is greater than 0°.

The wall block mold may also have a frame including first and secondopposing side walls and first and second opposing end walls and whereinthe at least one face forming surface having a stepped surface contourhas a face forming liner attached to one of the side walls. The faceforming liner may have a thickness at the top of the mold cavity whichis greater than a thickness at the bottom of the mold cavity to therebyprovide the outwardly stepped contour.

The wall block mold may further include first and second face formingsurfaces having a stepped surface contour. Additionally, angle α of thewall block mold may be in the range of about 1° to 10°. The plurality ofplanar surfaces of the mold may be substantially parallel and the moldmay have a plate which forms the bottom surface of the mold cavity.

Each ledge of the wall block mold may include a ledge surface that isangled downwardly from horizontal in a direction away from the moldcavity at an angle β which is greater than 0°. Additionally, angle β maybe in the range of about 1° to 10° and may more specifically be about4°.

In another aspect the present invention is a method of making a wallblock by providing a mold having first and second opposing side formingsurfaces and first and second opposing face forming surfaces, the firstand second side forming surfaces and first and second face formingsurfaces being positioned to form a perimeter of a mold cavity in theshape of a wall block, at least one of the face forming surfaces havinga stepped surface contour which steps outwardly from a top of the moldcavity to a bottom of the mold cavity, the stepped surface contourdefining a plurality of planar surfaces, each planar surface having anon-linear edge, each non-linear edge of a planar surface being joinedto a non-linear edge of an adjacent planar surface by a ledge, eachplanar surface being angled outwardly from vertical in the direction ofthe bottom of the mold cavity by an angle α which is greater than 0°,the mold further having a plate forming a bottom of the mold cavity. Themethod further including filling the mold cavity with a moldablematerial and removing the moldable material from the bottom of the moldcavity with the moldable material resting on the plate.

The method of making a wall block where the mold may also have a frameincluding first and second opposing side walls and first and secondopposing end walls and wherein the at least one face forming surfacehaving a stepped surface contour has a face forming liner attached toone of the side walls. The face forming liner may have a thickness atthe top of the mold cavity which is greater than a thickness at thebottom of the mold cavity to thereby provide the outwardly steppedcontour.

The method may further have a mold including first and second faceforming surfaces having a stepped surface contour. Additionally, angle αof the mold may be in the range of about 1° to 10°. The plurality ofplanar surfaces of the mold may be substantially parallel. The methodmay additionally have each ledge of the mold include a ledge surfacethat is angled downwardly from horizontal in a direction away from themold cavity at an angle β which is greater than 0°. Additionally, angleβ may be in the range of about 1° to 10° and may more specifically beabout 4°.

In another aspect the invention is a wall block comprising first andsecond opposing side surfaces, first and second opposing face surfaces,and opposing upper and lower surfaces, the side surfaces, face surfacesand upper and lower surfaces together defining a block body. The wallblock having at least one of the face surfaces having a stepped surfacecontour which steps inwardly from one of the upper surface and lowersurface of the block to the other of the upper surface and lower surfaceof the block, the stepped surface contour defining a plurality of planarsurfaces, each planar surface having a non-linear edge, each non-linearedge of a planar surface being joined to a non-linear edge of anadjacent planar surface by a ledge, each planar surface being angledinwardly from vertical by an angle α which is greater than 0°.

The wall block may include at least one face surface having a steppedsurface contour stepping inwardly from the upper surface of the block tothe lower surface of the block and additionally may have both the firstand second face surfaces having a stepped surface contour that may stepinwardly from the upper surface of the block to the lower surface of theblock. The wall block may have the plurality of planar surfacessubstantially parallel. Each planar surface of the wall block may haveangle α being in the range of about 1° to 10°. Each ledge of the wallblock may have a ledge surface that is angled downwardly from horizontalat an angle β which is greater than 0°. Additionally, angle β may be inthe range of about 1° to 10° and may more specifically be about 4°.

BRIEF DESCRIPTION OF THE DRAWINGS

A preferred form of the present invention will now be described by wayof example with reference to the accompanying drawings, wherein:

FIG. 1 is a perspective view of a mold of the present inventionillustrating first, second, third and fourth mold block cavities.

FIG. 2A is a front view of a first block face liner from the second moldblock cavity.

FIGS. 2B and 2C are cross-sectional views of the first liner from thesecond cavity taken along lines 2B and 2C, respectively.

FIG. 2D is a front view of a second block face liner from the secondmold block cavity.

FIG. 2E is a cross-sectional view of the second liner taken along line2E.

FIGS. 3A to 3D are front views of alternate embodiments of block faceliners of the present invention. FIG. 3E is a cross-sectional view ofthe embodiment of FIG. 3D taken along line 3E. FIG. 3F is an additionalfront view of an alternate embodiment of a block face liner of thepresent invention.

FIGS. 4A and 4B are perspective and bottom views, respectively, of ablock of the present invention.

FIGS. 5A and 5B are perspective and side views of a wall made with themanufactured block of the present invention.

FIGS. 6A to 6H are alternating front and back views, respectively, offirst and second block faces of the wall of FIGS. 5A and 5B.

FIG. 7 is a perspective view of a wall made with the manufactured blockof the present invention.

FIGS. 8A to 8H are alternating front and back views, respectively, offirst and second block faces of the wall of FIG. 7.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

The present invention is a method of manufacturing a unique block faceappearance using block face liners in a mold box. The block face linersin addition with other side liners and the mold box in which the linersare inserted are used to form multiple blocks at one time. The moldconsisting of the mold box, the liners, and a lower plate (productionpallet), forms cavities for the formation of blocks. Moldable materialis placed into the mold and consolidated by vibration for a timesufficient to allow the material to retain the desired block shape whenit is stripped or removed from the mold. In a manufacturing process, itis desirable to use one mold to form many blocks and for each block faceto be unique and different from each other. The block face liner forms ablock with a strata and/or ledge imprint resulting in the appearance ofnatural stone such as ledgestone or ashlar stone. The product (first setof blocks or slabs) is removed from the mold and moved to a curingstation while resting on its production pallet. Another productionpallet is positioned under the mold to receive the moldable materialwhich again fills the mold. In this way, many sets of multiple blocksare formed with one mold and many lower plates (production pallets).

This invention further comprises blocks with faces that have been formedwith the strata and ledges imprint. The invention further includes theconstruction of walls with blocks made in accordance with the invention.It is to be understood that the strata and ledge imprint could be formedon a vast assortment of blocks of different shapes and sizes and theblock disclosed herein is merely one example which should not beconsidered limiting as to the scope of the invention. An embodiment ofthe block disclosed herein is further described in commonly assigned andco-pending U.S. patent application Ser. No. 12/124,311 entitled “WallBlock and Wall Block System for Constructing Walls” hereby incorporatedherein by reference. These blocks are configured to be compatible witheach other in the construction of a retaining wall, a parapet wall, anda free-standing wall. Such walls may be straight, curved, or circular.The wall system is designed to be structurally sound and easy toinstall. The wall system is especially useful in constructing smallerwalls having a height of about 3 feet or less. Blocks may also beprovided with a side connection system wherein a side of the block isprovided with a channel or slot that is configured to engage acorresponding projection on an adjacent block. There may be one or morechannels or slots (and corresponding projections) on the block.Typically, and preferably, the side connection system is used on asmooth, un-textured side of the block. The side connection system is aparticular advantage in the construction of free-standing walls. This isbecause the side connection further stabilizes the wall and because theslots and projections prevent light from showing through the wall andtogether provide for a close fit of the blocks in the wall.

Referring to FIG. 1, there can be seen a multi-block mold box 10according to an embodiment of the present invention. Mold box 10generally includes opposing first and second side frame walls 2 and 4and opposing first and second end frame walls 6 and 8. Block moldcavities 20, 30, 40 and 50 are formed by divisional liner 12 which spansside frame walls 2 and 4, side liners 14, 15, 16 and 17 which arepositioned adjacent to end frame walls 6 and 8, and block face liners 22a, 22 b, 32 a, 32 b, 42 a, 42 b, 52 a and 52 b. Core bars 60 and cores61 (shown in dash) may also span side frame walls 2 and 4 and are usedto support core forms which create vertical voids in the blocks producedin the mold cavities. The space between the mold box frame walls andliners is either covered or comprises a solid material to ensure thatmaterial entering the mold box cannot be captured between the frames andliners. As known in the art the side and end space liners may beseparate parts bolted or affixed to the side and/or end frame walls.Though mold box 10 may have various dimensions, typical dimensions ofthis mold box are about 18.5 inches (47.0 cm) wide (i.e., the width ofboth the first and second end walls), 26.0 inches (66.0 cm) long (i.e.,the length of both the first and second side walls), and 4 inches (10.2cm) thick.

Block face liners 22 a, 22 b, 32 a, 32 b, 42 a, 42 b, 52 a, and 52 b maybe machine cut to create a particular irregular contoured strata andledge pattern that is widest at the top of the liner adjacent the top ofthe mold cavity and steps back gradually over a plurality of planes to anarrower width at the bottom of the liner adjacent the bottom of themold cavity. Block face liners 22 a, 32 a, 42 a, and 52 a may have thesame dimensions (heights of 4 inches and lengths of 12 inches) and blockface liners 22 b, 32 b, 42 b and 52 b may have the same dimensions(heights of 4 inches, lengths of 9 3/16 inches) according to the presentembodiment and each liner of similar dimension may have the same ordifferent machine cut strata and ledges pattern. It will be appreciatedthat these dimensions will be adjusted according to the size of the moldbox and mold cavities with which they are used.

FIG. 2A to 2E illustrate block face liner 32 a (FIG. 2A) and 32 b (FIG.2D) of the present invention. It should be noted that the featuresdescribed with respect to face liners 32 a and 32 b are equallyapplicable to face liners 22 a, 42 a, 52 a and 22 b, 42 b, and 52 b,respectively, except that the strata and ledge patterns may be varied asdesired. Block face liner 32 a (which can have a height of 4 inches anda length of 12 inches) has a greater surface area than block face liner32 b (which can have a height of 4 inches and a length of 9 and 3/16inches). Each stratum S or plane of the liner is preferably positionedat a tilt of angle α which equals about 1° to 10° and may morespecifically be about 1° from vertical and each ledge L of the stratumis preferably positioned with an angel β which equals about 1° to 10°and may more specifically be about 4° from horizontal. These angles andthe decreasing width of the liner from top to bottom help to ensure thatthe liner imprints the texture onto the block while creating enoughdraft in order for the block to be properly stripped from the mold box,and thus the liner, while retaining the imprint of the liner. However,the degree of angles can be changed or varied as desired and the statedangles or ranges should not be considered limiting as to the scope ofthe invention. The angle should be chosen to overcome any suctional orvacuum forces created by liquid in the mold material which would act toresist removal of the material from the mold cavity. Optional heat mayalso be added to the liners which functions to evaporate moisture toadditionally help eliminate any vacuum or suctional forces created bythe moisture in the mold material. Cross sectional views 2B and 2C ofFIGS. 2B and 2C illustrate the variations in irregularity of thecontours of the strata S of liner 32 a. The width of ledge L of eachstrata may be variable as desired and may be, for example, ⅛ of an inchper ledge. FIG. 2E illustrates cross sectional view 2E of the embodimentFIG. 2D illustrate the variations in width and length of the strata Sand ledges L of liner 32 b.

FIGS. 3A to 3F illustrate alternate embodiments of the strata and ledgestexture for a block face liner. Peak P of the liner of FIG. 3B imparts avalley or trench onto the face of the block which is formed from theliner. The valley/trench of the block face is meant to give theappearance that the face of the block is separated to appear as a leftand right side, or multiple random stones thereby adding to therandomness and variability of the block and thus the wall formed fromthe block. FIG. 3D illustrates an embodiment wherein the contours ofwider second, fourth and sixth terraces or strata 71, 73, and 75 arepreceded by substantially similar narrower first, third and fifthterraces or strata 70, 72, and 74, respectively. FIG. 3E illustratescross sectional view 3E of the embodiment of FIG. 3D and illustratesfirst, third and fifth ledges 80, 82 and 84 of the first, third andfifth terraces being wider than second and fourth ledges 81 and 83 ofthe second and fourth terraces (there is no ledge after the sixthterrace as the sixth terrace is at the bottom of the liner). Thisembodiment may also have peaks to imprint valleys onto the face of theblock and together with the imprinted wider terraces with similarnarrower terraces gives the block face the appearance of multipleindividual stones on three separate levels of the block face. Theimprint of the wider and narrower ledges onto the block face will alsocast more shadows onto some terraces and less onto other terraces. Itshould be noted that these are just a few of the possibilities thatcould be formed onto the liner due to the immense amount of variationspossible for the placement of the irregularly contoured strata andledges. For example, the face liners will be made to form a plurality ofstrata on the block faces. The strata will comprise planes that aresubstantially parallel to one another. Each stratum is bound by at leastone ledge which may be non-linear as shown in the drawings or, ifdesired, may be partially or entirely linear. The blocks are formed inthe mold cavity in inverted fashion with their bottom surfaces at thetop of the mold box and their top surfaces resting on the pallet at thebottom of the mold cavity. The strata on the blocks are formed to stepoutwardly from the top of the mold cavity to the bottom of the moldcavity so that the contour of any section along the face of the blocksteps outwardly to follow the contour of the face liner such as shown inFIGS. 2B, 2C and 2E in order to avoid the formation of pockets, grooves,or channels which would retain material when the block is removed fromthe mold box. Thus, in their position of use the strata on the blockfaces step inwardly from the top of the block to the bottom of the blockas best seen in FIG. 5B. It should be further noted that the block faceliners could be used to imprint a block face on differing styles andsizes of blocks and therefore the dimensions of the liner could varygreatly.

FIG. 3F illustrates an alternate embodiment for a block face liner whichshows a strata layer with a more wave-like pattern and smootherhorizontal curvilinear contour between each ledge.

As with conventional mold boxes, the mold box of the present inventionare configured to rest upon a pallet to form cavities. Masonry materialis deposited into block mold cavities 20, 30, 40 and 50 and laterremoved by stripper shoes on a head assembly that contact the masonrymaterial from above, compress it, and then push it through the moldwhile the mold is held firmly in a stationary position in the moldmachine in accordance with procedures well known to those of skill inthe art. The draft created by angles α and β and the narrowing width ofthe block face liners allow the masonry material to be properly strippedfrom the liner, thus releasing cleanly from the liner face. Prior to themasonry material being removed from the mold cavity heat may beintroduced to help ensure that the masonry material strips cleanly fromthe mold cavity and the strata and ledge imprint on the face/faces ofthe block keeps their shape and do not fragment. The masonry materialtypically is a rugged, weather resistant material, preferably (andtypically) zero-slump molded concrete. Other suitable materials includewet cast concrete, plastic, reinforced fibers, wood, metal and stone.Vibratory action compresses the material contained within the moldcavities. Stripper shoes which help push the molded block out of themold cavity do not touch the mold liners, division plates or divisionplate liners. The blocks are formed in the mold box with their bottomsurfaces facing upward, thus the block face liner which imparts thestrata and ledge imprint to the block face will be thicker towards thebottom surface of the block in the mold cavity (i.e., the top surfacewhen in the mold), and then step back and narrow toward the top surfaceof the block (i.e., the bottom surface when in the mold). This step-backimprint of the strata and ledges imparted by the face liner to the blockface helps to create shadows and dimension as light hits each plane onthe face of the block when it is inverted from how it is made in themold and placed in a wall assembly, giving the block a more natural andvisually pleasing appearance. It should be noted that the block couldalso be used bottom side up as desired, but in this case the sunlightwill not create shadows from the textured imprint.

FIGS. 4A and 4B illustrate a first embodiment of a first block 100 ofthis invention. Block 100 could be produced from any one or all ofcavities 20, 30, 40 and 50 of mold box 10. Block 100 comprises lowersurface 104 opposed and substantially parallel to upper surface 102, andopposing and substantially parallel first and second (also referred toas front and back) faces 106 and 108, respectively. The upper and lowersurfaces are separated by the thickness of the block. For the purposesof this description, first face 106 is shown facing the viewer in FIG.4A, however, it is to be understood that the first faces of some blocksand second faces of other blocks are in some situations exposed on thesame side when the blocks are used in a wall. Thus, the textured patternof strata and ledges is formed in both faces as described above. Theblock also comprises opposing and converging side surfaces 110 and 112(i.e., imaginary lines coincident with side surfaces 110 and 112 willeventually converge at some distance away from the second face or backof block 100) and are separated by the width of the block. Theconverging side surfaces result in first face 106 having a largersurface area than second face 108. First face 106 and second face 108have been molded with the strata and ledge imprint of the presentinvention. It should be noted that just one of the sides may have beenimprinted if so desired. Side surfaces 110 and 112 have curvilinearrecesses 114. Block 100 is preferably used with upper surface 102 facingup when constructing a wall to enhance the visual appearance of the walland to allow the plurality of stepped-back planes to cast shadow and adddimension to the block and wall as shown in FIG. 5B. It should be notedhowever that lower surface 104 could also be placed facing up if sodesired. Block 100 is provided with core 116 that extends through thethickness of the block. Preferably core 116 is circular.

Block 100 can be sized to desired dimensions. For example, the thicknessof the block can be 4 inches (10.2 cm), the width of the block can be 12inches (30.5 cm) along a first face 106 a and 9⅜ inches (23.8 cm) alongthe second face 108 a and the depth of the block between the first andsecond faces can be 7¾ inches (19.7 cm).

FIGS. 5A and 5B illustrate a wall made with multiple wall blocks havingmultiple different faces of strata and ledges imprints. The multipledifferent strata and ledge imprints give the wall a more random andnatural appearance enhancing the wall's visual appearance. Generally,when constructing a wall, a trench is excavated to a pre-selected depthand lined with a level base of granular material such as crushed stone.A base layer is then placed and leveled onto the crushed stone. Theblocks are placed side to side with a first face facing outward and thebottom surface facing downward. Optionally a “D” can be molded onto thebottom surface of the block (top surface when in the mold) to facilitateorientation (the “D” standing for down). A straight wall is produced byalternating the placement of the first and second faces of blocksrelative to each adjacent block (i.e. first face 106 of a block isplaced projecting outward and then the second face 108 of an adjacentblock is placed projecting outward). The adjacent block is placed andthe projection and slot of the side of one block fits securely into theslot and projection of the adjacent block. This interlocks adjacentblocks in a course giving the wall more stability without the use ofpins and pin receiving apertures typically found in prior art blocksystems. Once the base layer is laid, subsequent layers are placed oneon top of the next until the desired height is reached. Once the desiredheight is reached a capping layer may be added. Typically, the placementof blocks are vertically offset in adjacent courses in a running bondpattern. Curvilinear recesses (i.e. 114) of the side surfaces (i.e. 110and 112) form substantially circular cavities when laid side to side andare substantially similar in size and shape to the core (i.e. 116). Thecores and cavities overlap one another in adjacent courses producingvertical columnar cavities inside the wall structure. The circular shapeof the cores and cavities helps to maximize the alignment and functionalvolume of the vertical cavity. These columnar cavities may be filledwith a stabilizing material such as sand, gravel, sheer resistant fill(i.e. crushed stone), concrete, cement or the like, to give the walladded stability. The interlocking projections and slots along with thestabilizing material added to the vertical columnar cavities stabilizethe wall making it structurally sound without the use of traditionalstabilizing systems such as pins and the like. Optionally, constructionadhesive may be used to lack blocks and/or courses together with orwithout the use of stabilizing materials.

FIGS. 6A to 6H illustrates the wall of FIGS. 5A and 5B made withmultiple wall blocks having multiple embodiments of the strata andledges texture for the block faces. FIGS. 6A, 6C, 6E and 6G illustratefirst or front faces of blocks used in the construction of the wallwhile FIGS. 6B, 6D, 6F and 6H are the second or back faces of the blockswith first faces of FIGS. 6A, 6C, 6E and 6G, respectively. It should benoted that the first and second faces could have any combination ofsurface textures imprinted on them and could even have the same texture.It should also be noted that other types of wall blocks could beimprinted with the strata and ledge texture and that the block shown inthe drawings is just an example.

FIG. 7 illustrates a wall made with multiple wall blocks having multipledifferent faces of strata and ledges imprints. The multiple differentstrata and ledge imprints shows a strata layer with a more wave-likepattern and smoother horizontal curvilinear contour between each ledgeand gives the wall a more random and natural appearance.

FIGS. 8A to 8H illustrates the wall of FIG. 7 made with multiple wallblocks having multiple embodiments of the strata and ledges texture forthe block faces. FIGS. 8A, 8C, 8E and 8G illustrate first faces ofblocks used in the construction of the wall while FIGS. 8B, 8D, 8F and8H are second faces of the blocks with first faces of FIGS. 8A, 8C, 8Eand 8G, respectively. It should be noted that the first and second facescould have any combination of surface textures imprinted on them andcould even have the same texture. It should also be noted that othertypes of wall blocks could be imprinted with the strata and ledgetexture and that the block shown in the drawings is just an example.

Although particular embodiments have been disclosed herein in detail,this has been done for purposes of illustration only, and is notintended to be limiting with respect to the scope of the claims. Inparticular, it is contemplated that various substitutions, alterations,and modifications may be made to the invention without departing fromthe spirit and scope of the invention as defined by the claims. Forinstance, the choice of materials or variations in the shape or anglesat which some of the surfaces intersect are believed to be a matter ofroutine for a person of ordinary skill in the art with knowledge of theembodiments disclosed herein.

1. A wall block mold comprising first and second opposing side formingsurfaces and first and second opposing face forming surfaces, the firstand second side forming surfaces and first and second face formingsurfaces being positioned to form a perimeter of a mold cavity in theshape of a wall block, at least one of the face forming surfaces havinga stepped surface contour which steps outwardly from a top of the moldcavity to a bottom of the mold cavity, the stepped surface contourdefining a plurality of planar surfaces, each planar surface having anon-linear edge, each non-linear edge of a planar surface being joinedto a non-linear edge of an adjacent planar surface by a ledge, eachplanar surface being angled outwardly from vertical in the direction ofthe bottom of the mold cavity by an angle α which is greater than 0°. 2.The wall block mold of claim 1 further comprising a frame includingfirst and second opposing side walls and first and second opposing endwalls and wherein the at least one face forming surface having a steppedsurface contour comprises a face forming liner attached to one of theside walls.
 3. The wall block mold of claim 2 wherein the face formingliner has a thickness at the top of the mold cavity which is greaterthan a thickness at the bottom of the mold cavity to thereby provide theoutwardly stepped contour.
 4. The wall block mold of claim 1 whereinboth the first and second face forming surfaces have a stepped surfacecontour.
 5. The wall block mold of claim 1 wherein angle α is in therange of about 1° to 10°.
 6. The wall block mold of claim 1 wherein eachledge comprises a ledge surface that is angled downwardly fromhorizontal in a direction away from the mold cavity at an angle β whichis greater than 0°.
 7. The wall block mold of claim 6 wherein angle β isin the range of about 1° to 10°.
 8. The wall block mold of claim 7wherein angle β is about 4°.
 9. The wall block mold of claim 1 whereinthe plurality of planar surfaces are substantially parallel.
 10. Thewall block mold of claim 1 further comprising a plate which forms thebottom surface of the mold cavity.
 11. A method of making a wall blockcomprising: providing a mold having first and second opposing sideforming surfaces and first and second opposing face forming surfaces,the first and second side forming surfaces and first and second faceforming surfaces being positioned to form a perimeter of a mold cavityin the shape of a wall block, at least one of the face forming surfaceshaving a stepped surface contour which steps outwardly from a top of themold cavity to a bottom of the mold cavity, the stepped surface contourdefining a plurality of planar surfaces, each planar surface having anon-linear edge, each non-linear edge of a planar surface being joinedto a non-linear edge of an adjacent planar surface by a ledge, eachplanar surface being angled outwardly from vertical in the direction ofthe bottom of the mold cavity by an angle α which is greater than 0°,the mold further having a plate forming a bottom of the mold cavity;filling the mold cavity with a moldable material; and removing themoldable material from the bottom of the mold cavity with the moldablematerial resting on the plate.
 12. The method of claim 11 wherein themold has a frame including first and second opposing side walls andfirst and second opposing end walls and wherein the at least one faceforming surface having a stepped surface contour comprises a faceforming liner attached to one of the side walls.
 13. The method of claim12 wherein the face forming liner has a thickness at the top of the moldcavity which is greater than a thickness at the bottom of the moldcavity to thereby provide the outwardly stepped contour.
 14. The methodof claim 11 wherein both the first and second face forming surfaces havea stepped surface contour.
 15. The method of claim 11 wherein angle α isin the range of about 1° to 10°.
 16. The method of claim 11 wherein eachledge comprises a ledge surface that is angled downwardly fromhorizontal in a direction away from the mold cavity at an angle β whichis greater than 0°.
 17. The method of claim 16 wherein angle β is in therange of about 1° to 10°.
 18. The method of claim 17 wherein angle β isabout 4°.
 19. The method of claim 11 wherein the plurality of planarsurfaces are substantially parallel.
 20. A wall block comprising firstand second opposing side surfaces, first and second opposing facesurfaces, and opposing upper and lower surfaces, the side surfaces, facesurfaces and upper and lower surfaces together defining a block body, atleast one of the face surfaces having a stepped surface contour whichsteps inwardly from one of the upper surface and lower surface of theblock to the other of the upper surface and lower surface of the block,the stepped surface contour defining a plurality of planar surfaces,each planar surface having a non-linear edge, each non-linear edge of aplanar surface being joined to a non-linear edge of an adjacent planarsurface by a ledge, each planar surface being angled inwardly fromvertical by an angle α which is greater than 0°.
 21. The wall block ofclaim 20 wherein the at least one face surface having a stepped surfacecontour steps inwardly from the upper surface of the block to the lowersurface of the block.
 22. The wall block of claim 20 wherein both thefirst and second face surfaces have a stepped surface contour.
 23. Thewall block of claim 22 wherein the first and second face surfaces arestepped inwardly from the upper surface of the block to the lowersurface of the block.
 24. The wall block of claim 20 wherein angle α isin the range of about 1° to 10°.
 25. The wall block of claim 20 whereineach ledge comprises a ledge surface that is angled downwardly fromhorizontal at an angle β which is greater than 0°.
 26. The wall block ofclaim 25 wherein angle β is in the range of about 1° to 10°.
 27. Thewall block of claim 26 wherein angle β is about 4°.
 28. The wall blockof claim 20 wherein the plurality of planar surfaces are substantiallyparallel.